Beta-glucan, a cell wall polysaccharide, is present in grains, such as oats and barley, with the beta-glucan desired for human consumption because it has been found that beta-glucan can reduce serum cholesterol and lower the glycemic response in humans. The beta-glucan is found primarily in the endosperm cell wall portion of a barley grain. The beneficial effects of barley, and in particular beta-glucan, are discussed in articles by Macintosh et al. and Newman et al. (1,2). Because of the above discussed benefits it is desired to consume products containing an amount of beta-glucan, and more preferably an increased amount of beta-glucan.
It has further been found that barley often contains a relatively high amount of beta-glucan as compared to other grains so that barley is preferred for obtaining an adequate amount of beta-glucan. Generally, beta-glucan is found in barley in an amount ranging between about 5% and about 18% by weight of the barley. More typically, barley contains between about 5% and about 7% by weight beta-glucan, however, enhanced barley strains have been developed, Prowashonupana for example, which have between about 15% and about 18% by weight beta-glucan.
Even though certain strains of barley have comparatively high amounts of beta-glucan, it is desired to produce a barley flour or a barley fraction that has an even greater amount of beta-glucan than what is naturally found in barley flour derived from simply grinding barley grain. More specifically, regardless of the amount of beta-glucan found in barley, as it presently exists, it is desired to produce barley fractions or flours having enhanced amounts of beta-glucan. For example, if the barley grain starts with 18% by weight of beta-glucan, it is still desired to have a higher amount of beta-glucan in the barley flour or the barley fraction produced from such barley grain.
The barley grain can be ground into a flour or fraction for use in various food products, with it known that it is desired to have increased amounts of beta-glucan in the barley flour or fraction. In particular, the barley flour or barley fraction can be used to improve the functionality of beverages and the health benefits associated with the consumption of such beverages. Unfortunately, when barley flour is added to a beverage composition, the barley flour tends to impart a chalkiness or grittiness to the beverage. Chalkiness or grittiness is undesired because it is generally accepted that many consumers do not like beverages that leave a gritty feel in their mouth. For this reason, it is desired to have a barley product to add to beverages that does not result in a gritty chalky texture in the beverage. Thus, it is desired to have a barley product that, when used in beverages, has an enhanced amount of beta-glucan and that has an improved mouthfeel, so that a gritty or chalky texture is not imparted to the beverage containing the barley product. Consequently, it is desired to have methods which can be used to improve the mouthfeel of the barley flour and to enhance the amount of beta-glucan found in the barley flour.
It is believed one reason barley flour or barley products have a gritty chalky mouthfeel is because when they are mixed with liquid to form a beverage, the beverage has a relatively low viscosity and because the barley flour is uncooked. Further, it is known that increased viscosity often improves the mouthfeel of a beverage. Thus, it is desirable to have a barley flour or barley fraction that will potentially increase the viscosity of beverage which has the barley flour or fraction added thereto.
Many methods for forming barley flour or barley fractions have been developed which attempt to obtain comparatively high amounts of beta-glucan from barley. In particular, wet extraction methods have been used to successfully isolate high beta-glucan fractions from barley flour or grain allowing for the production of a barley flour or fraction having high levels of beta-glucan. Wet extractions are also desired because they produce a barley flour or fraction having a desirable mouthfeel and texture so that when beverages are made from the barley flour or fraction, the gritty chalky texture is not imparted to the beverage. Wet extraction processes, however, presently can be very expensive. For this reason, it is preferred to have a less expensive dry milling process for producing a barley flour or fraction.
Dry milling followed by sieving or air classification can be used to isolate or obtain high beta-glucan fractions from barley. It has been found, however, that dry milling produces a barley flour that has a low viscosity when added to liquid and that more importantly has an undesirable mouthfeel. In particular, the mouthfeel of the dry milled barley flour tends to be chalky and also tends to have a raw grain flavor. It has further been observed that the percentage of the high beta-glucan fraction recovered is typically low. For example, typically less than 50% of the original starting material is recovered as a high beta-glucan fraction. As such, it is desired to have a cost effective dry milling method for producing a barley flour or fraction that results in a barley flour or fraction having a high beta-glucan content, a high viscosity, a desirable mouthfeel, and a high beta-glucan fraction recovery.
A patent of particular interest that discloses a method for dry milling and preparing a high soluble fiber barley fraction is U.S. Pat. No. 5,063,078, issued to Foehse. Such patent discloses a method of pearling a barley flour followed by dry milling and then pin milling the barley flour such that from about 30% to about 80% of the particles are less than 50 microns. After pin milling the barley flour, the barley flour is classified to separate a coarse barley fraction from the remainder of the barley flour, with the coarse barley fraction containing a high amount of beta-glucan. As such, the Foehse patent discloses a method that results in a barley fraction having a high beta-glucan content, however, it is believed that the barley flour or fraction produced according to the Foehse patent is gritty, has a low viscosity, and contains a raw grain flavor. Thus, while the method of the Foehse patent results in a barley fraction having a sufficient amount of beta-glucan, the mouthfeel is believed to be undesired. It should further be pointed out that the Foehse patent does not teach cooking the barley flour.
Thus, it is greatly desired to be able to use a barley flour or barley fraction in beverages because the barley will contain beta-glucan, which is beneficial to human health. However, a number of problems associated with the use of barley flour or barley fractions containing beta-glucan must be overcome. First, it is desired to increase the percentage of beta-glucan found in the barley flour or fraction, as an increased amount of beta-glucan will provide increased benefits to consumers. Second, even if a barley flour or fraction having an increased amount of beta-glucan is produced, it is desired to have a fraction or flour that is more palatable, meaning it is desired to have a fraction or flour having improved mouthfeel and viscosity.